$10 million more operating profit. Does Harbor Coffee, our fictional coffee business, keep more from each sales dollar?
It reports FY2 revenue of $1,050 million and operating profit of $210 million. In FY3, those figures rise to $1,100 million and $220 million.
A bigger profit is only half the story: you also need the sales that produced it. Put both years on a $100 sales scale to see whether Harbor keeps a larger cut.
Three cuts of the same sales dollar
The revenue lesson found a $50 million sales increase. The income statement gives you several stopping points between those sales and final profit. A profit margin is the fraction of revenue left at one of those points.
Gross margin uses gross profit. Operating margin uses operating income. Net margin uses net income. All three divide by the same period's revenue.
Harbor's FY3 operating margin is $220 million ÷ $1,100 million × 100 = 20%. Read that as 20 cents of operating profit per dollar of sales.
Margin uses sales as its denominator; markup uses cost.
Calculate Harbor's three margins
Harbor's FY3 accounts also report $440 million gross profit and $150 million net income. Using millions of US dollars throughout:
- Gross: 440 ÷ 1,100 × 100 = 40%.
- Net: 150 ÷ 1,100 × 100 ≈ 13.64%.
That gives $40 gross profit, $20 operating profit and about $13.64 net profit per $100 of sales. The bars shrink as Harbor deducts more costs. The $20 is already inside the $40; adding the bars would count the same profit more than once.
FY2 uses its own revenue of 1,050 and reported profits of 420, 210 and 142.5:
- Gross: 420 ÷ 1,050 × 100 = 40%.
- Operating: 210 ÷ 1,050 × 100 = 20%.
- Net: 142.5 ÷ 1,050 × 100 ≈ 13.57%.
The changes are in percentage points, or pp: 10% to 12% is two points.
| Margin | FY2 | FY3 | Change (pp) |
|---|---|---|---|
| Gross | 40% | 40% | 0.00 |
| Operating | 20% | 20% | 0.00 |
| Net | 13.57% | 13.64% | +0.06 |
The net-margin change is calculated before rounding: 13.6363… − 13.5714… ≈ 0.06 points.
Harbor earns more operating profit because it sells more, with the same 20 cents left from each dollar. Only net margin improves.
Read the trend and ask why
FY1 confirms the pattern: 40% gross margin, 20% operating margin and 13.50% net margin. Across all three years, the improvement happens below operating profit.
The responsible line is interest expense: $20 million in both FY2 and FY3. Its share of sales falls from 20 ÷ 1,050 × 100 ≈ 1.90% to 20 ÷ 1,100 × 100 ≈ 1.82%. The interest bill stays the same; more sales carry it.
Harbor's tax rate stays at 25%: $47.5 million on $190 million pretax profit in FY2, then $50 million on $200 million in FY3. The smaller interest burden per sales dollar lifts net margin even after tax.
Use the gaps to choose where to look. If gross margin holds steady while operating margin falls, inspect the operating expenses between them. If only net margin moves, start with interest, other income and taxes.
A margin points you to a line in the accounts; it does not tell you why that line changed. Check whether prices, costs or the sales mix changed before choosing an explanation.
High depends on the business
In Aswath Damodaran's January 2026 US industry snapshot, grocery and food retail has a net margin of 1.32%; system and application software has 25.49%. These industry aggregates divide combined net income by combined sales. They describe each group, not a target for every member.
High depends on what the business does to earn a dollar. Compare similar products, customers and cost classifications. Harbor's mix of packaged coffee and shops matters more than the word "coffee" in its name.
Fictional Tessel Software has a 78% gross margin in FY3, yet its $45 million net profit on $1,586 million revenue gives just 2.84% net margin. A high gross margin can leave very little at the bottom.
When a good margin misleads
Keep sales and total profit beside the percentage. Suppose a business earns $20 on $100 of sales, then $18 on $80. Its margin rises from 20% to 22.5% while its profit falls. Losing lower-margin sales or cutting spending needed for future growth can flatter the ratio.
The three margins need not descend, either. Tessel's FY3 operating profit of $40 million plus $20 million interest income, less $15 million tax, leaves $45 million net profit. Interest income more than covers tax, so net margin exceeds operating margin.
For a sudden change, read the accounting-policy note for cost classifications, the acquisition note for businesses added, and the tax note for tax effects. A gain from selling an asset also deserves a look. The adjusted earnings lesson explains how to judge items a company removes from its profit measure.
Margins tell you how much profit sales produce. Earnings per share asks how much of that profit belongs to each share.
In short
- Each margin divides a different profit subtotal by the same period's revenue.
- A 20% margin means 20 cents of that profit per dollar of sales.
- A high margin in one industry can be low in another.
- The gap between margins tells you which part of the accounts to investigate.
- A rising margin can accompany falling profit. Keep the dollars beside the percentage.